bioRxiv (Cold Spring Harbor Laboratory),
Journal Year:
2024,
Volume and Issue:
unknown
Published: Dec. 31, 2024
Cyclic
oligonucleotide-based
antiviral
signaling
systems
(CBASS)
are
bacterial
anti-phage
defense
operons
that
use
nucleotide
signals
to
control
immune
activation.
Here
we
biochemically
screen
57
diverse
Trends in Microbiology,
Journal Year:
2024,
Volume and Issue:
32(9), P. 828 - 831
Published: June 27, 2024
The
study
of
bacterial
immune
systems
has
recently
gained
momentum,
revealing
a
fascinating
trend:
many
form
large
supramolecular
assemblies.
Here,
we
examine
the
potential
mechanisms
underpinning
evolutionary
success
these
structures,
draw
parallels
to
eukaryotic
immunity,
and
offer
fresh
perspectives
stimulate
future
research
into
immunity.
Nature Communications,
Journal Year:
2025,
Volume and Issue:
16(1)
Published: Feb. 13, 2025
The
astounding
number
of
anti-phage
defenses
encoded
by
bacteria
is
countered
an
elaborate
set
phage
counter-defenses,
though
their
evolutionary
origins
are
often
unknown.
Here,
we
report
the
discovery
orphan
antitoxin
counter-defense
element
in
T4-like
phages
that
can
overcome
bacterial
toxin-antitoxin
defense
system,
DarTG1.
DarT1
toxin,
ADP-ribosyltransferase,
modifies
DNA
to
prevent
replication
while
its
cognate
antitoxin,
DarG1,
a
NADAR
superfamily
ADP-ribosylglycohydrolase
reverses
these
modifications
uninfected
bacteria.
We
show
some
carry
DarG1-like
domain
protein,
which
term
anti-DarT
factor
(AdfN),
removes
ADP-ribose
from
during
infection
thereby
enabling
DarTG1-containing
find
divergent
proteins
unrelated
likewise
exhibit
anti-DarTG1
activity,
underscoring
importance
ADP-ribosylation
bacterial-phage
interactions,
and
revealing
function
substantial
subset
superfamily.
Toxin-antitoxin
systems
make
up
branch
immune
system.
Johannesman
et
al
demonstrate
have
co-opted
counter
ADP-ribosyltransferase
Nature Communications,
Journal Year:
2024,
Volume and Issue:
15(1)
Published: Nov. 11, 2024
Retrons
are
bacterial
genetic
elements
that
encode
a
reverse
transcriptase
and,
in
combination
with
toxic
effector
proteins,
can
serve
as
antiphage
defense
systems.
However,
the
mechanisms
of
action
most
retron
effectors,
and
how
phages
evade
retrons,
not
well
understood.
Here,
we
show
some
retrons
other
systems
by
producing
specific
tRNAs.
We
find
expression
retron-Eco7
proteins
(PtuA
PtuB)
leads
to
degradation
tRNA
bioRxiv (Cold Spring Harbor Laboratory),
Journal Year:
2025,
Volume and Issue:
unknown
Published: March 26, 2025
Reverse
transcriptases
(RTs)
have
well-established
roles
in
the
replication
and
spread
of
retroviruses
retrotransposons.
However,
recent
evidence
suggests
that
RTs
been
conscripted
by
cells
for
diverse
antiviral
defense.
Here
we
determine
structures
a
type
I-A
retron,
which
explain
how
RNA,
DNA,
RT,
HNH-nuclease
four
molecules
an
SMC-family
ATPase
assemble
into
364
kDa
complex
provides
phage
We
show
phage-encoded
nucleases
trigger
degradation
retron-associated
leading
to
disassembly
retron
activation
HNH
nuclease.
The
nuclease
cleaves
tRNA
Ser
,
stalling
protein
synthesis
arresting
viral
replication.
Taken
together,
these
data
reveal
paradoxical
perpetuation
elimination
genetic
parasites.
Journal of Virology,
Journal Year:
2024,
Volume and Issue:
98(11)
Published: Oct. 24, 2024
ABSTRACT
Toxin/antitoxin
(TA)
systems
are
present
in
nearly
every
prokaryotic
genome
and
play
the
important
physiological
roles
of
phage
inhibition
by
reducing
metabolism
(this
includes
persistence
for
extreme
case
complete
cessation
metabolism),
genetic
element
stabilization,
biofilm
formation.
TA
have
also
been
incorporated
into
other
cell
systems,
such
as
CRISPR-Cas
quorum
sensing.
For
simplest
best-studied
case,
proteinaceous
toxins
antitoxins
(i.e.,
type
II),
toxin
activity
is
masked
direct
binding
antitoxin.
A
long-standing,
unresolved
question
field
how
activated
when
bound
to
at
nanomolar
affinity.
The
current
paradigm
envisions
preferential
degradation
antitoxin
a
protease,
but
this
highly
unlikely
that
protease
cannot
discriminate
between
because
both
structured.
Strikingly,
recent
results
from
several
studies
show
one
likely
mechanism
activation
conformational
changes
complex
result
release
or
protein
trigger,
phages,
thermally-driven
refolding
dynamics.
bioRxiv (Cold Spring Harbor Laboratory),
Journal Year:
2024,
Volume and Issue:
unknown
Published: July 11, 2024
The
astounding
number
of
anti-phage
defenses
encoded
by
bacteria
is
countered
an
elaborate
set
phage
counter-defenses,
though
their
evolutionary
origins
are
often
unknown.
Here,
we
discover
orphan
antitoxin
counter-defense
element
in
T4-like
phages
that
can
overcome
the
bacterial
toxin-antitoxin
defense
system,
DarTG1.
DarT1
toxin,
ADP-ribosyltransferase,
modifies
DNA
to
prevent
replication
while
its
cognate
antitoxin,
DarG1,
ADP-ribosylglycohydrolase
reverses
these
modifications
uninfected
bacteria.
DarG1-like
protein,
which
term
anti-DarT
factor
NADAR
(AdfN),
removes
ADP-ribose
from
during
infection
thereby
enabling
DarTG1-containing
AdfN,
like
superfamily
ADP-ribosylglycohydrolases
found
across
domains
life.
We
find
divergent
proteins
unrelated
likewise
exhibit
anti-DarTG1
activity,
underscoring
importance
ADP-ribosylation
bacterial-phage
interactions,
and
revealing
function
a
substantial
subset
superfamily.
Cell Reports,
Journal Year:
2024,
Volume and Issue:
43(10), P. 114857 - 114857
Published: Oct. 1, 2024
Highlights•Phage-encoded
DNA
cytosine
methyltransferase
(Dcm)
is
a
trigger
of
the
retron
Ec86
system•Dcm
methylates
stem-loop
region
msDNA
to
activate
Ec86•Cryo-EM
analysis
reveals
Ec86-effector
filaments
containing
NAM
and
ADPr•The
filament
capable
hydrolyzing
NAD(P)+SummaryRetrons
are
class
multigene
antiphage
defense
systems
typically
consisting
reverse
transcriptase,
non-coding
RNA,
cognate
effector.
Although
triggers
for
several
have
been
discovered
recently,
complete
mechanism
by
which
these
detect
invading
phages
mediate
remains
unclear.
Here,
we
focus
on
system,
elucidating
its
modes
activation
mechanisms
action.
We
identified
phage-encoded
as
system
demonstrated
that
activated
upon
multicopy
single-stranded
(msDNA)
methylation.
further
elucidated
structure
tripartite
assembly
primed
Dcm
nicotinamide
adenine
dinucleotide
(NAD+).
These
findings
provide
insights
into
underscore
an
emerging
theme
through
supramolecular
complex
assemblies.Graphical
abstract
Trends in Microbiology,
Journal Year:
2024,
Volume and Issue:
unknown
Published: Oct. 1, 2024
HighlightsNoncoding
RNAs
(ncRNAs)
have
emerged
as
pivotal
players
in
bacteria–phage
conflicts.Many
bacterial
immune
systems
depend
on
ncRNAs
for
both
structure
and
function.ncRNAs
are
key
regulators
of
responses.Phages
use
to
counteract
defenses.AbstractThe
evolutionary
arms
race
between
bacteria
phages
has
driven
the
development
diverse
anti-phage
defense
mechanisms.
Recent
studies
identified
noncoding
conflicts,
including
CRISPR-Cas,
toxin–antitoxin
(TA),
reverse
transcriptase
(RT)-based
defenses;
however,
our
understanding
their
roles
immunity
is
still
emerging.
In
this
review,
we
explore
multifaceted
immunity,
offering
insights
into
contributions
anti-defense
mechanisms,
influence
regulatory
networks,
potential
biotechnological
applications.
Finally,
highlight
outstanding
questions
field
spark
future
research
directions.